Method and apparatus for the distillation of tar



July 25, 1933.

sfP. MILLER METHODv AND APPARATUS FOR THE DISTILLATION OF TAR 4 Sheets-Sheet l Filed Jan. 10, 1929 INVENTOR ATTORNEYS s. P. MILLER 1,919,240 METHOD AND APPARATUS FOR THE DISTILLATION OF TAR July 25, 1933.

4 Sheets-Sheet 2 Filed Jan. 10, 1929 INVENTOR M Maia ATTORNEYS July 25, 1933.

5. P. MILLER METHOD AND APPARATUS FOR THE DISTILLATION 0F TAR 4 Sheets-Sheet 3 Filed Jan. 10, 1929 INVENTOR 4 1M m AITORNEYS 4 Sheets-Sheet 4 July 25, 1933. s. P. MILLER METHOD AND APPARATUS FOR THE DISTILLATION OF TAR Filed Jan. 10, 1929 Patented July 25, 1933 UNITED STATES PATENTv OFFICE STUART IPARMELEE MILLER, OF ENGLEWOOD, NEW JERSEY, ASSIGNOR TO THE BARRETT COMPANY, OF NEW YORK, N.

Y., A. CORPORATION OF NEW JERSEY METHOD AND APPARATUS FOR THE DISTILLATION 0F TAR Application filed January 10, 1929. Serial No. 331,600.

This invention relates to improvements in the distillation of tar, and includes an improved method of distillation and improved apparatus therefor. More particularly, the invention relates to an improved process and apparatus in which high melting point pitch and low melting point pitch are simultaneously produced, and in which heavier and lighter oils are simultaneously produced.

According to the present invention, tar is subjected to distillation by bringing it into direct and intimate contact with hot highly heated gases, such as hot coke oven gases, the

gases from gas retorts, etc., and the distillation is so carried out that the hot enriched gases from the distillation leave at a high temperature; and these hot enriched gases are then employed for the heating and distillation of additional tar by bringing them into indirect heat interchanging relation therewith, whereby the hot enriched gases are cooled and oils condensed therefrom simultaneously with the heating and distillation of additional tar. The distillation by direct contact wih the highly heated gases is so regulated as to produce a high melting point pitch, as well as enriched gases leaving the still at a high temperature. ther distillation of tar by indirect heating with the hot enriched gases is so regulated as to produce a low'me lting point pitch and a relatively light distillate; The high melting point pitch and the low melting point pitch from the two separate distillations are drawn oil" as separate products, the vapors from the soft pitchand the enriched gases from the hard pitch still are left separate, and after condensation the (listillates from the two stills are separately drawn 03, giving simultaneously different characters of distillates. The present invention provides an improved process and apparatus whereby high melting point pitch, e. g. up to around 400 F. melting point or higher can be produced simultaneously with the production of a low melting point pitch which may be suitable as a flux or for use on roads or other purposes;

and in which a heavy creosote oil and a light carbolic or tar acid oil can be separately produced andrecovered from the separate dis- The fur-- tillations. The second distillation is accomplished with the heat contained inthe hot enriched gases from the first distillation.

The apparatus of the present invention includes a still connected to a source of. highly heated gases, such as hot coke oven gases and having means therein for bringing the tar. or pitch to be distilled into direct and intimate contact with the highly heated gases to effect distillation of the tar or pitch and the production of high melting point pitch so that the hot enriched gases leaving the still are at a high temperature. These hot enriched gases then pass to the second still where they are employed to heat the tar in the second still by indirect contact therewith, and where the hot enriched gases are themselves cooled and oils condensed therefrom. The second still is thus a combined still and condenser, or heat interchanger, in which the hot enriched gases are cooled and the tar is thereby heated. The tar from the second still is @thus distilled to producelow melting point pitch and a relatively low boiling distillate, and the distillate and pitch are pitches may be made. For exampleywhen pitch of 180."200 F. melting point is produced as thehard pitch, dehydrated or lightly distilled tar or soft pitchmay result from the indirect heating and distillation.

- The still in which' the tar is distilled to produce high meltingpointpitch by direct contact with highly heated gases is advantageously one in which there is a thorough and intense spraying of the tar and pitch into the gases in the still so that the highly heated gases entering the still will be immediately cooled to a lower temperature approaching that of the pitch, and so that the tar and pitch will be rapidly distilled and heated to a high temperature approaching that of the gases, and so that a high melting point pitch will be produced, for example, a pitch having a melting point up to around 400 F. or higher. In such a still, the hot gases will be thoroughly scrubbed and cleaned from susticularly advantageous for use at a coke oven pended impurities, and the admixed gases and vapors will leave the still at a high temperature, for example, around 250 to 400 C. where the highly heated gases enter the still at a higher temperature of around 550 to 800 C. or higher.

The second still, which is a combined still and condenser, may be one in which the tar is passed through pipe coils externally heated by the Hot enriched gases, or one in which the hot enriched gases pass through pipe coils surrounded externally by the tar. Various types of heat interchangers can be employed for bringing about indirect contact of the hot enriched gases and of the tar to be heated and distilled. In generaha countercurrent flow of the tar and of the hot enriched gases is more advantageous, inasmuch as the tar can be thereby heated to a higher temperature, approaching that of the hot enriched gases, while the hot enriched gases can themselves be cooled to a low temperature approaching that of the cold tar entering the still, thereby accomplishing a more complete condensation of the oils from the hot enriched gases, and the heating of the tar to a higher temperature and with increased distillation of light nilS therefrom. The second still is provided with a condenser for the oil vapors, and the low melting point pitch is drawn ofi' as a separate product. The oils condensed from the hot enriched gases employed for heating the second still will also be drawn ofl as a separate oil product, or as separate oil fractions where the condensation is. of a fractional character.

The present process and apparatus is parplant or a.coal gas plant for distilling coal tar to produce a high yield of distillate oil therefrom, for example, up to around or more, and a high melting point pitch, for example up to 400 F. melting point or hi gher, by distilling the tar by direct contact with hot coke oven gases, coming directly from the coke ovens at a high temperature. In this way, a high melting point pitch and an unusually high oil yield can be obtained from the tar distilled. Moreover, in distilling tar in this way, the hot enriched gases leaving the still are at an unusually high temperature, for example, at a temperature around 250 to 400 C. These hot enriched gases are then employed by passing them through an indirect heat interchange'r to heat and distill tar which, by proper countercurrent arrangement of the flow of the tar and of the hot enriched gases, can be heated to a temperature approaching that at which the hot enriched gases leave the first still and enter the second still as heated gases. Tar can be heated in the second still to produce a lower melting point pitch, for example, a pitch of around 110 F. melting point, or up to around 140 or 150 F. melting point, with the corresponding production of a distillate distillation in the first still, and makes use. of the waste heat in the hot enriched gases from the first still for effecting the distillation in the second still.

This combined method and apparatus enables a creosote oil to be directly recovered from the first still and a lighter carbolic oil or tar acid oil from the second still; while simultaneously producing a high melting point pitch from the first still and a low melting point pitch from the second still, and

accomplishing the cooling and condensation of a greater or less amount of the oils from the hot enriched gases from the first still s1- multaneously with the effecting of the distillation in the second still.

In the operation of the respective stills, the rate at which the tar will be supplied to the still can be regulated. In the first still, where a high melting point pitch is produced, the rate of feed of tar to the still will be regulated so that a high melting point pitch will be produced and'a high percentage yield of distillate oils. In the second still the rate at which tar is supplied can be regulated to give directly a pitch of higher or lower melt-- ing point and a distillate representing a higher or lower percentage of the tar distilled. By regulating the rate at which tar is supplied to the second still, the extent of distillation and the melting point of the pitch can be reguated, but the melting point of the pitch will be much lower than that produced in the first still and the distillate will be a lower boiling distillate representing a smaller percentage of the tar distilled.

The second still may advantageously be tar is pumped under pressure and in which it is heated externally by the hot enriched gases, with subsequent discharge of the hot tar into a vapor boxwhere the vapors are removed and condensed, and from which the low melting point pitch is withdrawn. Such a pipe coil still will serve as a condenser for the hot enriched gases, with the result that more or less of the vapor content of these gases will be condensed and can be drawn oil as an oil which has a much higher boiling point range than the distillate from the pipe coil still.

in the form of a pipe coil through which the v The invention will be further describedin apparatus located at a coke oven plant and embodying the present invention and adapt- I cooled and granulated.

ed for carrying out the process of the present invention.

Fig. 1 is a plan view of a coke oven plant equipped with apparatus for carrying out the invention;

Fig. 2 is an elevation of the apparatus shown in Fig. 1 with parts in section;

Fig. 3 is a section on the line 3-'3 of Fig. 2;

Fig. 4 is a plan view of a modified arrangement of apparatus which may be used in connection with a coke oven plant for carrying out the invention;

Fig. 5 is an elevation of the apparatus shown in Fig. 4;

Fig. 6 is a section on the line 6-6 of Fig. 5.

Fig. 7 is a section on the line 77 of Fig. 5.

Fig. 1 shows a coke oven battery 5, equipped with uptake pipes 6, a collector main 7 centor box 8, and cross-over main 9, which may be of the usual type and which are shown schematically.

At the rear of the ovens is a still 10 connected with selected ovens through uptake pipes 11. By proper manipulation of valves in the uptake pipes 6 and these uptake pipes 11 the gases from selected ovens may be passed either to the collector main 7 or to the still 10. The hot gases from the selected ovens are passed through the uptake pipes 11 into the still 10 when the still is in operation and are brought into intimate contact with an intensive spray of tar or pitch in the still. A roll 12 located at one side of the still a short distance from the curved wall 13 is rapidly rotated by the motor 14 in such a way that it sprays the tar or pitch in the still up into the gases and thoroughly scrubs and cleans the gases and forces the tar up over the wall 13 so as to prevent the accumulation of coke or hard pitch on the still walls.

The tar, which is preferably preheated is admitted to the still through the pipe 15, and on passing through the still is sprayed up into the gases as an intense spray which thoroughly scrubs and cleans the gases entering the still, and removes entrained particles of pitch, etc., from the gases, and the tar or pitch is simultaneously distilled by the hot gases. The flow of tar and pitch through the main and the preheating of the tar before entering the main are preferably so regulated that a pitch of high melting point is produced, e. g. in the neighborhood of about 400 F. or higher. The pitch is withdrawn from the still throughthe drawoff 16 and may be sprayed by water from 17 as it is drawn ofl from the still and thus The granulated pitch is collected in 18 together with the water and suitably separated therefrom and used for any desired purpose.

The gases leave the still at a high temperature, for example around 250 to 400 C. and pass up through the settling chamber 19, where entrained particles of pitch separate from the gases and return to the still. The gases then pass over through the main 20 into the heat interchanger 21. The uptake pipes, still, settling chamber and main 20 are heavily insulated as shown at 22.

The. heat interchanger 21 is a combined still and condenser. The hot gases enriched in condensible constituents entering the heat interchanger through the main 20 are cooled within the heat interchanger by tar which is admitted at 23 and passes up through the pipe coil 24 in indirect contact with the hot gases. in a direction counter-current to the flow of the gases. The gases are cooled and oils are condensed changer and simultaneously the tar which enters the heat interchanger at 23 is heated to a temperature approaching that of the hot enriched gases entering at 21. The oil condensed from the hot enriched gases in 21, which may be a heavy oil such as a heavy creosote oil, is withdrawn at 25 and run into a suitable storage tank 26. The gases passing through the heat interchanger are cooled and leave the heat interchanger through the pipe 27 from which they may be passed to further condensing means, and means for the recovery of ammonia and light coal tar oils. Such means may comprise a direct condenser 28 in which the gases are sprayed with water and from which ammonia liquor and light oils are drawn off to' the decanter 29 and separated into the ammonia storage tank 30 and the light oil storage tank 31. The

gases may then pass through an exhauster.

32 to theordinary means for the recovery ofl ammonia and the usual coke oven light 01 s.

The heated tar from the pipe coil 24 leaves the heat interchanger 21 through the pipe 33. and enters a vapor box 34. In this vapor box the'light constituents of the tarwhich have been vaporized in the coil are permitted to separate from the unvaporized residue, and, in addition, due to lowering of pressure on escape from the coil, some further vaporization is caused by conversion of a portion of the sensible heat of the tar to latent heat of vaporization in the vapors. The unvolatilized constituents are drawn off at 35 as a low melting point pitch to a suitable storage tank 36. The vapors set free and formed in the vapor box 34 pass off through the main 37 to a suitable condenser 38 which is here shown as an indirect condenser. The condensed oils from the condenser 38 drain into a suitable light oil storage tank 41.

The pipe 33 is preferably well insulated as shown at 43, in order to prevent loss of heat from the highly heated tar leaving the heat therefrom within the heat inter- The flow of tar is preferably interchanger, so that the maximum distillapitch and a light oil distillate. In the drawings, hot coke oven gases pass from selected ovens of a coke oven battery thru uptake pipes 50 into a heavily insulated hot gas Header 51 and thence into the still 52. Tar is admittd to the still at 53. The tar which is preferably preheated may be sprayed into the gases in the settling chamber Where its temperature will be raised, and thenfed into the still 52, as by collecting it at the bottom of the settling chamber and passing it through the pipe 53' to the still.

he gases are sprayed with an intensive spray of tar by means of a roll 54 situated similarly to the roll 12 of the former figures and rapidly rotated, e. g. at 10001200 B. P. M. by the motor 55. The tar is sprayed into the hot gases as an intense spray and ole-tars them and the operation may be so controlled that the tar is distilled to pitch of a melting point of about 400 F. or higher. The pitch is withdrawn at 56 granulated and recovered in the pitch stor-. age tank 57 by means similar to that described in connection with the preceding fig- I ures. The hot enriched gases pass from the still up through the settling chamber, 58 where particles of pitch entrained in the gases are removed therefrom by gravity and the cleaned hot enriched gases pass over through the main 59 into the heat interchanger 60. The uptake pipes, the header 51, the still, the settling chamber, and the main 59 are heavily insulated as shown at 61.

The sensible heat of the gases and vapors and the latent heat of the vapors entering the heat interchanger 60 are utilized at least in part in heating tar which is brought into indirect contactwith them. The tar may be heated in one stage or, as shown in the drawings, a two stage tar heater may be employed.

This two stage heater comprises the heat in-' terchangers and 62. The tar enters the heat interchanger 62 at 63 and passes up through this heat interchanger-through the pipe coil 64 and then through the pipe coil 65 in the heat interchanger 60. The hot gases enter the heat interchanger 60 from the main 59 and pass down through this heat interchanger and through the main 66 into the heat interchanger 62 and out from this heat interchanger through the iiuai ra'j '67, The

and may begases pass through the heat interchangers in a direction which in general is counter-current to the flow of the tar.

The heat interchangers serve both as condensers and a still. The enriched gases entering the heat interchanger 60 are cooled and heavy oils are condensed therefrom which are withdrawn at 68 and may be separately collected in the heavy oil storage tank 69. The gases then pass into the heat interchanger 62 where they are further cooled and a lighter oil fraction is condensed from the gases and is withdrawn through 70 to the oil storage tank 71. As an alternative method, a total condensate from the two condensers may be drawn off into eitheivof the storage tanks 69 or 71 by means of the connecting pipe 72.

The tar which enters the heat interchangers at 63 first comes, into contact with the cooler gases leaving thru pipe 67 and is gradually heated as it flows through the heat interchangers preferably in a direction countercurrent to the flow of the hot gases. It leaves the heat interchanger 60 through the pipe 73 and is conducted to the vapor'box 74 Where vapors formed in the coil are permitted to separate and the sensible heat of the tar causes volatilization of the lighter constituents of the tar when placed under the vacuum which exists in the vapor box due to the vacuum pump arrangement to be described below. The gases leaving the heat interchangers through'the main 67 pass to a condenser and thence to an exhauster and means for recovering lighter oils, ammonla, ctc., not shown.

The vapor box 74 is connected through the indirect condenser 75 and separator 7 5 toa vacuum pump 76. The valve 77 controls the reduction inpressure from the COIl tO the vacuum chamber. The vacuum vapor box 74 is provided with a barometric column 7 8 through which the residue, -which is a'low melting point pitch, is withdrawn to the storage tank 79.

through which condensate is withdrawn to the storage tank 81.

According to a preferred method "of operating, the hot gases from the coke ovens pass through the still 52 and distill the tar admitted thereto to produce a high meltlng point pitch e. g. of a melting point around 400 F.v The gases leave the still at a high temperature e. g. of about 250 to 400 C. and pass up through the settling chamber and over to the heat interchangers where the heat of the gases and vapors is utilized. to bring the tar admitted at 63 to a temperature approaching that of the entering hot gases. Where the gases and vapors leave the still 52 at a temperature in the neighborhood of 400 (3., the tar leaving the heat interchanger through the pipe 73 will be at a somewhat Similarly the condenser 75 is 1 provided with a barometric column 80 lower temperature, but sufiiciently high to distill lower boiling constituents from the tar in the vapor box so as to produce a pitch e. g., with a melting point of 110 F. or higher up to, for example, about 140 to 150 F., or higher by proper regulation of the tar flow and maintenance of suliicient vacuum on the vapor box.

Heavy and lighter oils will be condensed from the enriched gases leaving the still 52 in the heat interchangers (S0 and 62, and they may be collected together to give a total clean oil condensate or they may be separately collected to give separate clean oil fractions. The vapors leaving the vapor box 7 4 are condensed'in the indirect condenser 75 and give a light oil distillate which is collected in 81.

The heat of the hot coke oven gases is thus utilized to operate two distillation systems, one by direct contact with the tar in the still 52 and the other by indirect contact between the tar and the hot enriched gases from the still 52 in the heat interchangers 60 and 62. The distillates are separately collected and separate pitch products are produced.

I claim:

1. The method of distilling coal tar and of producing simultaneously distillate, a high melting point pitch and a low melting point pitch, which comprises distilling the tar by direct contact with highly heated inert gases and regulating'the supply of tar and the contact of the tar and pitch with the gases so as to produce pitch of high melting point and enriched gases at high temperature, drawing off the high melting point pitch so produced, passing the hot enriched gases into indirect contact with tar to heat the tar and simultaneously cool the hot enriched gases, regulating the supply of tar to be so heated so as to remove distillate therefrom and produce a low melting point pitch and so as to condense oil from the hot enriched gases, drawing off and separately condensing the distillate,h and drawing OK the low melting point itc 2. The method of distilling coal tar and of simultaneously producing distillate, high melting point pitch and low melting point pitch, which comprises subjecting the tar to distillation by direct contact with hot coke oven gases at a suiiiciently high temperature, and with suiiiciently intimate contact of the tar and pitch with the gases, so that high melting point pitch is produced, and so that hot enriched gases are produced, drawing oii the high melting point pitch, passing the hot enriched gases into an indirect heat interchanger and condenser in indirect contact with tar to be distilled, passing tar at a regulated rate through such interchanger and condenser in indirect contact with the hot enriched gases and regulating the supply of tar so as to effect condensation of oils from such gases and to heat the tar to a temperature sufficient to remove a distillate therefrom and to produce a low melting point pitch, and separately drawing ofl the low melting point pitch itlld the distillate and condensing the distilate.

3. The method of distilling coal tar and of producing simultaneously distillate, high melting point and low melting point pitch which comprises distilling the tar by direct and intimate contact with hot coal carbonization gases at a suificient temperature to effect distillation of the tar and the production of high melting point pitch and of hot enriched gases, withdrawing the hot enriched gases and cooling the same in an indirect heat interchanger and condenser in indirect contact with tar to be preheated and distilled, pumping tar under pressure through a pipe coil located in saidinterchanger and condenser in indirect heat interchangingrelationwith thehot enriched gases and regulating the supply of tar so that it is heated to a temperature sufiicient to effect partial distillation of the tar, discharging the preheated tar in to a vapor box, drawing ofi the vapors and condensing them, and drawing 0d the low melting point pitch from the vapor box.

4. The method of distilling coal tar and of producing simultaneouslydistillate, a high melting point pitch and a low melting point pitch, which comprises distilling the tar by direct contact with highly heated inert gases and regulating the supply of tar and the contact of the tar and pitch with the gases so as to produce pitch of high melting point and enriched gases at high temperature, drawmg ofi the high melting point pitch s0 produced, passing the hot enriched gases into indirect contact with tar to heat the tar and simultaneously cool the hot enriched gases, passing the tar continuously into'indirect contact w th the hot gases and then to a chamber mamtained under a vacuum to produce 011 vapors and a pitch residue, drawing ofi the pltch residue, drawing ofl' the oil vapors and condensing the oils therefrom, and drawing 0 the condensates resulting from the cooling of the hot enriched gases by indirect contact with the tar.

5. The method of distilling coal tar and of producing simultaneously distillate, high melting point pitch and low melting point pitch which comprises distilling the tar by direct and intimate contact with hot coal.

carbonization gases at a suflicient temperature to effect distillation of the tar and the production of high melting point pitch and of hot enriched gases, withdrawing the hot enriched gases and cooling the same in an indirect heat interchanger and condenser in indirect contact with tar to be preheated and distilled, pumping tar under pressure through a pipe coil located in said interchanger and condenser in indirect heat interchanging relation with the hot enriched gases and regulating the supply of tar so that v it is heated to a temperature sufficient to effect partial distillation of the tar, discharging the preheated tar into a vapor box maintained under a vacuum, drawing off the vapors and condensing them, and drawing off the low melting point pitch from the vapor box.

6. An apparatus for distilling tar and for 10 producing simultaneously distillate, high melting point pitch and low melting point pitch, comprising a still having means for supplying thereto highly heated gases and for supplying tar thereto and removing pitch therefrom and having means therein for bringing about intimate contact of the tar or condensation of oils from the gases, means for supplying tar to be distilled to the heat interchanger and for bringing it into indirect contact with the hot enriched gases, a vapor separating chamber with means for conveying heated tar from the heat interchanger thereto, means for taking off the distillate from said vapor separating chamber and for condensing the same, and means for withdrawing low melting point pitch from said vapor separating chamber.

7 An apparatus for distilling tar and for simultaneously producing high melting point pitch and low melting point pitch, comprising a still locatedat a coke'oven plant and connected with a plurality of coke ovens so that highly heated coke oven gases enter the still, means for supplying tar to the still and for withdrawing pitch therefrom, means for bringing the tar and pitch into intimate contact with the gases in the still to produce high melting point pitch and hot enriched gases leaving the still, an indirect heat interchanger and condenser for the hot enriched gases in which they are brought into indirect contact with tax to be heated and distilled,

means for supplying tar to such condenser in regulated amounts, vapor separating means connected with the heat interchanger for separating vapors from the resulting preheated and partially distilled tar, and means in connection therewith for drawing oft low meltmg point pitch resulting from such distillation. 1

8. An apparatus for distilling tar and for producing simultaneously distillate, high melting point pitch and low melting point pltch, comprising a still provided with means for introducing thereto highly heated coal carbonization gases, means for supplying thereto tar to be distilled and for removing pitch therefrom, means for bringing about thorough and intimate contact of the tar and enriched gases leave the still, an indirect heat interchanger and condenser arranged for the passage of the hot enriched gases therethrough to effect coolingand condensation of oils therefrom, a pipe coil arranged in said indirect interchanger and condenser and means for continuously pumping tar therethrough to effect heating thereof to a temperature sufficient to efiect partial distillation thereof, a vapor box into which the pipe coil discharges, a condenser for condensing vapors separated in said vapor box, and a separate draw-off for low melting point pitch from said vapor box.

9. An apparatus fordistilling' tar and for producing simultaneously distillate, high melting point pitch and low melting point pitch, comprising a still having means for supplyingthereto highly heated gases and for supplying tar thereto and removing pitch therefrom and having means therein for bringing about intimate contact of the tar or pitch and the gases to produce high melting point pitch and hot enriched gases, a heat interchanger, means for supplying tar to be distilled to the heat interchanger and for bringing it into indirect contact with the hot enriched gases, a vacuum chamber arranged to receive the preheated tar from the heat interchanger and means for maintaining a vacuum therein and for taking off the vapors therefrom and for condensing them and for withdrawing the pitch therefrom. f

10. An apparatus for distilling tar and for producing simultaneously distillate, high melting point pitch and low melting point pitch, comprising a still provided with means for introducing thereto highly heated coal -carbonization gases, means for supplying thereto tar to be distilled and for removing pitch therefrom, means for bringing about thorough and intimate contact of the tar and pitch with the gases in the still whereby high melting point pitch can be produced and hot enriched gases leave the still, an indirect heat interchanger and condenser arranged for the passage of the hot enriched gases therethrough to effectcooling and condensation of oils therefrom, a pipe coil arranged in said heat interchanger and condenser and means for continuously pumping tar therethrough to effect heating thereof to a temperature suflicient to effect partial distillation thereof, a vapor box into which the pipe coil dissTUART PARMELEE MILLER.

' charges, means for maintaining a vacuum on 

